Portable pap device with humidification

ABSTRACT

A portable, efficient, integrated humidification system for use, e.g., with a positive airway pressure devices. The portable, efficient, integrated humidification system described herein offers many advantages over current humidification systems! There are many advantages to a portable respiratory humidifier. Portability reduces the amount of space the humidifier occupies in the user&#39;s bedroom environment. Portability enhances travel for the user. With less to pack, carry, and manage, the user is more likely to remain adherent to therapy when not at home. Portability allows for better utilization in recreational vehicles, while camping, in foreign countries, in the sleeping cabins of trucks or airliners, and on marine craft.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

BACKGROUND

Obstructive sleep apnea (OSA) occurs when tissue in the upper airwayblocks the airway during sleep. The brain will sense the rise in CO2,and will wake up the person so that breathing resumes. Such an event iscalled an apnea. A partial airway blockage causing an awakening iscalled a hypopnea. A person is unlikely to remember such awakenings, butsleep is disrupted. The severity of obstructive sleep apnea is measuredby the frequency of awakenings, as shown in the table below.

Apneas + Hypopneas/Hour OSA Classification 0-5 Normal  5-15 Mild 15-30Moderate 30+ Severe

Untreated, OSA not only leaves patients chronically fatigued, but italso carries significant cardiovascular consequences.

Positive Airway Pressure, or PAP, is the most widely used and the mosteffective treatment for OSA. In PAP, a bedside compressor suppliespressurized air to the patient's airway through a hose and mask. The airpressure is set sufficiently high to maintain an open airway duringsleep. Examples of PAP devices may be found, e.g., in U.S. Pat. No.8,316,848; U.S. Pat. No. 8,453,640; and U.S. Pat. No. 8,353,290, thedisclosures of which are incorporated herein by reference.

Many OSA patients who use PAP have difficulty using their PAP systemswhen traveling. Most PAP systems are both bulky and too fragile to packin checked luggage. For travel, patients prefer small, light PAPsystems. Despite recent introduction of some portable PAP systems, thereremain significant shortcomings in their design.

Smaller, more travel-friendly PAP machines are being introduced to themarket. However, they either lack humidification or, if they include it,it requires extra bulk.

Many travelers leave their humidification systems at home when theytravel. The humidification units for many PAP systems are just as largeas the flow generator. Humidification units are comprised of a largereservoir for holding water, and technology to convert the fluid waterinto a mist or vapor. The bulk of the water chamber is not compressible,and therefore inhibits portability and travel.

Standard humidification systems for positive airway pressure devicestypically comprise a heated water reservoir and a flow path for the PAPairflow to pass over the heated water, thereby becoming humidified.These systems have several shortcomings. Among the shortcomings are sizeand power requirements. Bulky systems take up valuable personal spaceand are less portable for travel. These systems also have higher powerrequirements, as they must maintain a large mass of water at a heatedtemperature during the entire use. This results in a less efficient,bulkier system. Further, these systems require daily maintenance andcleaning. Some are also prone to spilling. Spilling water in the bedroomenvironment, near electronics, electrical power, and personal items, canbe a significant problem and dissuade humidifier use.

SUMMARY OF THE DISCLOSURE

The portable, efficient, integrated humidification system describedherein offers many advantages over current humidification systems.

There are many advantages to a portable respiratory humidifier.Portability reduces the amount of space the humidifier occupies in theuser's bedroom environment. Portability enhances travel for the user.With less to pack, carry, and manage, the user is more likely to remainadherent to therapy when not at home. Portability allows for betterutilization in recreational vehicles, while camping, in foreigncountries, in the sleeping cabins of trucks or airliners, and on marinecraft.

For the humidification system, a fluid source is required. In most casesthis is in the form of a water reservoir. Classic humidification systemsincorporate a tank for holding the fluid. These tanks typically hold300-500 mL or more. Travel with such a bulky tank is burdensome.

Another limitation of many existing humidification systems is therecommendation that distilled water be used. This is due to theevaporative designs used and the buildup of minerals left behind. Inultrasonic humidifiers, there is a concern that minerals in the watercan be aerosolized and inhaled into the lungs of the user.

In all humidification systems, there are concerns of microbial organismsin the water, especially if the water reservoir and path are notconsistently emptied and cleaned. Many users do not clean their devicesas frequently or thoroughly as recommended by the manufacturer.

For these reasons, the incorporation of filtration and sterilizationcapabilities into the system may be desired.

In one embodiment of the invention, the micro-humidifier is integratedinto the PAP base unit.

In another embodiment of the invention, the micro humidifier is anattachment unit that can be connected to any PAP machine to providehumidity to the airflow. This connection could occur through thestandard tubing fittings. These fittings are commonly 22 mm in diameter.The connection could also be made using adaptors. The humidificationunit can work using several different mechanisms well known in the art,including: evaporation, steam, ultrasonic, diffuser.

The unit can be powered through a standard wall plug or with batteries.

In a further embodiment, the humidification unit to which the bottle isattached can deliver its humidified air through a small tube that isconnected to the tubing or mask interface near the patient to humidifythe air.

The bottle could be connected to sit upright, upside down, or lay on itsside. It could have a tube extending into it for the sourcing of thewater. Bottles of various sizes could be used with the same standardizedfitting. The bottle and device could also be fashioned to convenientlyattach to the sleeping environment. They could attach to the headboard,sideboards, mattress, under the bed, side table, lamp or otherattachments surfaces.

In a further embodiment of the invention, the humidification apparatuscan also heat the water, providing heated humidification.

Another aspect of this invention is a humidification system thatovercomes the shortcomings of the existing conventional systems. This isachieved according to one embodiment of the invention by providing asmall, lightweight, and energy efficient humidification element in-linewith the airflow tubing. This integrated hose humidifier can be part ofthe hose tubing, either in section or full length. The humidificationelement is fed from a separate connected reservoir of fluid. This fluidreservoir can be integrated with the hose humidifier. Alternatively, thefluid reservoir can be housed separately from the humidification hose.Fluid passes from the reservoir through small tubing to thehumidification hose, where a humidification element transforms the fluidinto vapor within the air path of the tube, where it is then carried bythe flow to the user.

Several key advantages are offered by such a system. Many advantages areparticularly well suited to the goals of portability and ease of use.

Separating the fluid reservoir from the humidification element offersmany unique advantages. For example, the fluid reservoir can be replacedwith a new one when empty. As described in more detail below, the fluidreservoir can take the form of a standard screw-top water bottle,commonly available worldwide. Further, the ability to discard andreplace the fluid reservoir reduces the cleaning and maintenance burdenon the user.

A fluid reservoir that is independent of the humidification element alsoreduces or eliminates leaks and spillage. As the reservoir can becompletely enclosed, and does not depend on the ability to allow air topass above the water to get humidified, it does not have the inherenttendency to leak that conventional systems have. Additionally, in manyembodiments it is not dependent on one certain orientation with respectto gravity to work properly. This offers a significant advantage.Conventional humidification systems require that the system bemaintained upright. This results in bulky systems to ensure they do nottip over from movement during use. One of the challenges of producing acompact humidification system is the requirement of conventionalhumidifiers to be anchored with an upright orientation. As device sizeis reduced, the tendency to tip and spill is increased. The inventiondescribed herein allows the independent reservoir to be placed in manydifferent positions that still provide for successful transfer of waterfrom the reservoir to the humidification element. Likewise thehumidification element does not require a certain orientation withrespect to gravity in order to work properly.

Since the humidification is integrated into the airflow hose, it allowsfull, unencumbered movement of the tubing during use. Conventionalhumidification systems do not enable movement of the hose during use.They effectively create a new, stationary base to which the tubingattaches. They are not designed to move with the tubing.

The ability to integrate the humidification directly into the tubingalso allows for the humidification to occur at any point along thetubing between the flow generator and the user. Placing thehumidification closer to the user offers many benefits. Thehumidification has less area in which to condense and cause rain out,therefore more of the humidification will reach the end user instead oflining the interior of the flow path. The ability to place thehumidification element anywhere along the tubing allows for variouscombinations of heating before, during or after the humidification ofthe airflow. The compact and lightweight humidification elementsdescribed herein enable this advantage.

Further, for applications where the flow generator may be worn on thebody or suspended near the user, it is significantly advantageous toseparate the fluid reservoir from the humidification. It is not desiredto wear 300-500 cc of water on the body throughout the night. Thissystem allows the reservoir to be contained separately, and just thetubing with integrated humidification element to be worn by the user.

Conventional humidification systems incorporate a tank for holding300-500 mL of fluid. A significant improvement employed by the inventionis the ability to use standard threaded water bottles or similarcontainers as the water reservoir. Most water bottles have a standardthread opening (such as SPI 28MM thread specs). The fitting can bedesigned to fit the majority of flat water bottles in the marketplace.Multiple adaptors can be offered to allow for pressurized bottles,non-pressurized bottles, and bottles of varying threads availableinternationally. In addition to the ability to work with almost anywater bottle available, water reservoirs custom designed for theapplication can be provided with the same threaded opening to allow forattachment. The custom reservoir could be used in a home environment, orother situations when a more repeatable, robust reservoir is desired.When traveling, a disposable water bottle can be used as the reservoir.This liberates the user from having to bring a reservoir with them—theysimply procure a water bottle wherever they are, use it, and can leaveit behind when they are done with it. This significantly reduces theamount of material with which a user must travel.

In another embodiment, the fluid reservoir is comprised of a collapsiblereservoir. This collapsible reservoir could be in the form of a bottlemade of a flexible material and folding design which can accordion intoa small volume for transport, and expand into a full size reservoir foruse. This enables portability for travel and expandability during use.One such design fulfilling this goal is a reservoir with preformed foldsin the walls and made of an elastomer which can easily expand andcollapse.

A further unique advantage of the system of this invention is theefficiency with which the fluid is aerosolized into the air path. In oneembodiment, an ultrasonic nebulizer creates vaporized droplets of waterwith low energy demand. A further embodiment allows for the selectiveactivation of the system. Conventional humidification systems are alwayson or always off. The system described herein can be cycled on and offrapidly. This can be timed with the respiratory cycle, thereby providinghumidified air during inspiration, but not during expiration. Thisreduces the unnecessary waste of energy and water, and can reduce theincidence of “rain out,” a common annoyance for users whereinhumidification condenses in the circuit and water droplets run onto theface of the user.

Heated humidification has been shown to enhance patient comfort. In someembodiments of the invention, the system incorporates heating to createheated humidification for the user. Conventional humidifiers heat largemasses of water and allow air to pass over them to create heatedhumidification. The invention described here allows for the activeheating of the moisturized air. In some embodiments, the mist itself isheated by a heating element incorporated in the ultrasonic unit. Thefluid may be heated in its reservoir, while it travels from thereservoir to the humidification element, in the small antechamber to thehumidification element, by the humidification element itself, or once itis inside the air path tubing, or some combination thereof. Heatingsmaller amounts of water just before, during or after transformationinto mist is more efficient than maintaining an entire reservoir attemperature. Heating elements incorporated in the tubing heat the mistand air as it passes by. A combination of heating the water prior tovaporization and heating the mist in the air path may offer the mostefficient results.

Heating is achieved through the use of a heating element. The heatingelement can be a resistance heater, such as a wire. The material can bemetal or a composite material. The heating element can take on severaldifferent geometries. Coiled wire offers increased surface area forimproved heat transfer. Other heating geometries which maximize heattransfer can be employed. One particular geometry of interest allowslaminar flow and a high surface area for heat transfer. This is achievedby forming multiple longitudinal channels that create multiple parallelair paths, leading to laminar flow and allowing for significantlyincreased surface area for heating. Exposure of the air path to theheating element can be optimized from a cross-sectional perspective, aswell as a longitudinal perspective. This allows for the maximum heattransfer in the smallest possible device size.

A combination of heating both the water on its way to the humidificationelement and the air in the air path can offer the best heat profile,comfort, and efficiency.

Several materials can be used to insulate the heating elements of thesystem from the other components. These materials include but are notlimited to: ceramics, silicones, heat tolerant polymers, polyimides, andother material with adequate heat resistant properties.

According to another aspect of the present invention, fluid must betransported from a separate reservoir to an integrated humidificationtube.

For this purpose, a small pump can be provided with the system to pumpwater from the reservoir to the humidification element. This micro pumpcan operate continuously, or be tuned to deliver water only as needed.Further, the pump can be adapted to deliver water timed with therespiratory cycle. Thus, when a user inhales, the inhaled air can bewell humidified, while during the rest of the respiratory cycle the airneed not be humidified. The humidification system may contain sensors tosense the respiratory cycle to enable the timing of the humidification.These sensors may include pressure, flow, or temperature sensors. Thehumidification device may alternatively communicate with the flowgenerator machine to utilize its sensors to indicate the timing of therespiratory cycle. This timing helps save water, energy, and reduces thenegative side effects of rainout from too much water condensing andcollecting in the airflow tubing. Excess water can impede airflow, andif it drips onto the user's face, it causes an unpleasant arousal fromsleep and deters usage of the PAP device.

According to one embodiment of the invention, gravity is used to movethe water from the reservoir to the humidification element. By placingthe water reservoir at a higher level than the humidification element,water will flow to the humidification element, keeping it supplied withwater. This rate can be regulated by the height difference between thereservoir and the humidification element, or by the incorporation offlow restricting elements in line. The ultrasonic element can bedesigned with micro holes, such that the water does not flow through itunless it is activated. This prevents forward flow from the reservoirthrough the humidification element and into the air path when notdesired, thereby inherently regulating the rate of fluid flow.

According to another embodiment of the invention, weight or pressure canbe used to transport the water from the reservoir to the humidificationelement. The water reservoir is in the form of a flexible bladder. Thisbladder is placed under a weight, thereby pressurizing it enough todrive fluid flow to the humidification element. One such way to achievethis weight is by placing the reservoir bladder under the sleeper. Itcould be placed under the pillow or the mattress. Alternatively, thefluid bladder is pressurized by placing it within an inflatable sleeve.Inflation of the sleeve exerts pressure on the fluid bladder, drivingfluid flow to the in-line humidifier. Alternatively, the fluid bladderitself can be pressurized by pumping air into it with a pump. Pumps canbe automated, hand-driven, or simple one-way valve structures used toinflate the fluid bladder.

According to another embodiment of the invention, wicking materialsprovide a method to transport fluid from the reservoir to thehumidification element. Wicking materials pull fluid from the reservoirto the humidification element. As the fluid is converted to humidity,more fluid is drawn from the reservoir to replace it. This approach hasthe advantage of being low power. The materials provide for the movementof the water, without needing additional energy. Furthermore, it doesnot require that the reservoir be necessarily placed higher than thehumidification element.

Combinations of the above approaches to move water from the reservoir tothe humidification element are also possible, and may offer distinctadvantages. For example, a pumping system which includes wicking matrixmaterial in the line can help regulate the rate at which the fluid istransported through the system. This can help avoid under or overtransporting water to the humidification element. Likewise, gravity andwicking aspects could be combined to offer a system that requires noadditional power to move water and is also self-regulating.

For reasons described above, means for filtration and purification ofthe water is desired. For ultrasonically based systems, distilled watercan be used. If regular tap water is used, a filtration material can beincorporated to remove minerals inherent in the water.

According to another embodiment of the present invention, a filtrationmedia is incorporated into the system between the fluid reservoir andthe humidification element to remove undesired substances from thewater. In one embodiment, the filtration involves a demineralizationfilter. This filter removes minerals in the water, producing water thatis free of particulate contaminants and suitable for consistentrespiration. This allows for the use of tap water in the system. Tapwater often contains minerals that are not desirable to be aerosolizedand inhaled. There are filtration media with demonstrated performance inremoving minerals from water. Suitable media include those commonlyfound in water filtration applications such as reverse osmosis systems,steam cleaning apparatus, aquarium filtration and water softeners. Theability to use tap water is a significant advantage, particularly in thetravel environment, as it can be difficult and burdensome to locate asource of distilled water when travelling. It is certainly inconvenient,and in some cases not possible, to travel with large amounts ofdistilled water. The ability to use tap water in the humidificationsystem is a significant advancement.

This filter can be placed inside the adaptor which threads onto thefluid reservoir. This filter location prevents minerals from enteringthe rest of the system, keeping it cleaner and safer. Additionally, thefilter can be easily changed from such a position, and also has theopportunity to dry out between uses if desired. The filter canalternatively be placed at the terminus of the hose inserted into thefluid reservoir. The filter may also be placed anywhere along the fluidpath between the fluid reservoir and the humidification hose.

A demineralization filter can be achieved compactly, as the volume ofwater to be demineralized is relatively small compared to other commonapplications. Demineralization resins offer efficacy adequate to treat ayear's worth of humidification water with a few ounces of material orless. In a further embodiment, the demineralization material can changecolors to indicate to the user when it is time to replace the filter.

Demineralization can be achieved using reverse osmosis. High pressure isapplied through semi-permeable membranes which remove minerals.Demineralization can also be achieved through the use of resins whichexchange the minerals that make the water hard, such as calcium andmagnesium ions, with other, softer ions such as sodium or potassium.Resins may be in the form of gel beads comprising cross-linkedpolystyrene, divinylbenzene, or similar materials. In anotherembodiment, electrodeionization can be used to remove minerals from thewater—a process utilizing resins, semi-permeable membranes, andelectricity to remove unwanted ions and minerals.

According to another embodiment of the invention, sterilization andpurification elements are incorporated into the system. An ultravioletlight source is utilized to disinfect the water. Ultraviolet light hasbeen demonstrated to kill microorganisms that may develop in a fluidenvironment. UV light will kill fungi, mold, bacteria, viruses and otherpotentially problematic growth organisms. This feature ensures greatersafety for the user, and also provides ease of use. Typicalhumidification systems recommend that the user perform regular andtime-consuming cleanings of the device. Due to the burden of suchcleanings, many users do not regularly or adequately clean theirsystems. A self-cleaning and self-regulating system offers significantadvantages to the user in both safety and convenience. The UV lightsource can be incorporated in the fluid reservoir, along the fluid pathfrom the reservoir to the humidification element, within thehumidification element, or inside the hose with the humidified air path.In one embodiment, the UV light source is provided in the antechamber ofthe humidification element. The UV light prevents growth ofmicroorganisms and helps keep the unit clean, further reducing themaintenance burden on the user.

According to another embodiment of the invention, anti-bacterial andanti-microbial materials or coatings are incorporated into the system toslow or prevent the growth of microorganisms. These materials andcoatings are placed along the fluid and air path.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 illustrates one embodiment of a portable humidification systemfor a PAP system according to this invention.

FIG. 2 illustrates another embodiment of a portable humidificationsystem according to the invention.

FIG. 3 illustrates yet another embodiment of a portable humidificationsystem according to the invention.

FIG. 4 illustrates still another embodiment of the portablehumidification system according to this invention.

FIG. 5 illustrates yet another embodiment of the portable humidificationsystem according to this invention.

FIG. 6 illustrates an embodiment of a portable humidifier according tothis invention.

FIG. 7 is a longitudinal cross-sectional view of the portable humidifiershown in FIG. 6.

FIG. 8 is a longitudinal cross-sectional view of yet another portablehumidifier according to this invention.

FIG. 9 is a cross-sectional view of a fluid reservoir adaptor accordingto this invention.

FIG. 10 is a cross-sectional view of the fluid reservoir adaptor of FIG.9, showing an alternative outlet geometry for the fluid reservoiroutlet.

FIG. 11 is a cross-sectional view of a portable humidifier componentaccording to another embodiment of the invention.

FIG. 12 is a longitudinal cross-sectional view of a portable humidifieraccording to another embodiment of the invention.

FIG. 13 is a longitudinal cross-sectional view of a portable humidifieraccording to yet another embodiment of the invention.

FIGS. 14 a, b, and c are diagrammatic cross-sections showing variousembodiments allowing wicking and regulation of fluid flow from the fluidreservoir to the humidification element.

FIG. 15 shows a cross-sectional side view of an alternative embodimentfor the humidifier of this invention.

DETAILED DESCRIPTION

FIG. 1 illustrates one embodiment of a portable humidification systemfor a PAP system according to this invention. A flow generator 10produces pressurized airflow, which passes through a lumen of a firstair conduit section 12 connecting the flow generator to a humidifier 27,where it is humidified and then continues traveling through a lumen ofan air conduit section 13 to a patient interface 14, such as a mask or anasal cannula. Humidifier 27 is integrated with, and supported by, theair conduit 12/13. As shown, the flow generator 10 is resting on a table11 or other surface.

Humidifier 27 is part of a portable humidification system 20. Inaddition to the humidifier 27, the portable humidification system 20 hasa fluid reservoir 21, a humidifier inlet 25, a humidifier outlet 26, apower source connection 23, and a conduit 28 connecting the fluidreservoir 21 to humidifier 27 through an optional reservoir adaptor 22.The fluid reservoir 21 is filled with the desired humidification fluid,in many cases distilled water, undistilled water, tap water, and bottledwater. The fluid reservoir 21 is pictured situated above the tubingintegrated humidifier 27, such that the fluid will flow from thereservoir to the humidifier by means of gravity. In this embodiment, theportable humidification element 20 may be powered via the powerconnection 23, shown here as accessing a wall power outlet 24.Alternatively, other power sources, such as batteries, may be used.

FIG. 2 illustrates another embodiment of a portable humidificationsystem according to the invention. Here the fluid reservoir 21 is shownlower than the tubing integrated humidifier 27. In this embodiment, apump (not shown) integrated into the system at either the reservoiradaptor 22 or the tubing integrated humidifier 27 provides the means totransport the fluid from the fluid reservoir 21 to the tubing integratedhumidifier 27. This allows the system to operate independent of gravity.

FIG. 3 illustrates another embodiment of a portable humidificationsystem according to the invention. In this embodiment the tubingintegrated humidifier 27 is placed in close proximity to the flowgenerator 10. This arrangement allows the tubing 13 connecting thehumidifier to the patient interface 14 to be standardized. Power for thehumidifier 27 can be supplied via the power cord 23 to a power outlet 24as shown. Alternatively, power for the humidifier 27 can be routedthrough the flow generator 10.

FIG. 4 illustrates another embodiment of the portable humidificationsystem according to this invention. In this embodiment the fluidreservoir 21 is situated on its side. This arrangement can allow for theportable humidifier 27 and the fluid reservoir 21 to be placed out ofthe way of the user, for example on the floor. Fluid reservoir intaketube 29 is positioned in the fluid reservoir 21 to pull fluid fortransport to the humidification element.

FIG. 5 illustrates another embodiment of the portable humidificationsystem. In this embodiment the fluid reservoir 21 is placed higher thanthe tubing integrated humidifier 27. This allows gravity to provide theforce for fluid to flow from the fluid reservoir 21, through thereservoir adaptor 22, through the reservoir tubing 28, of which aportion of the reservoir tubing 28 is here shown to be collocatedalongside the air conduit 13. The fluid is delivered to the tubingintegrated humidifier 27, and humidification is provided very close tothe user interface 14. This setup provides the advantage of providingthe humidification in close proximity to the user. In some embodiments,the humidification can occur just proximal to the patient interface, aslittle as about 1 cm or less from the mask. In some embodiments, thehumidification can occur between about 5 and 50 cm from the userinterface. This reduces the incidence of excess humidification, reducesrainout, and reduces the amount of tube heating required to preventrainout. Additionally, the tubing integrated humidifier 27 cancommunicate, either wired or wirelessly, with the flow generator 10 toselectively cycle on and off, providing humidification only during thepart of the respiratory cycle (inspiration, expiration) when it isneeded. This increases the efficiency of the system, both from an energystandpoint and from a water use standpoint. This selective cyclingfurther reduces the incidence of rainout.

FIG. 6 illustrates an embodiment of a portable humidifier 27 accordingto this invention. This tubing integrated humidifier 27 has an inlet 25and an outlet 26 for the flow of air through the tubing section. Alsoshown is an inlet port 30 for the humidification chamber, where thefluid is introduced. The humidifier lid 31 seals against the humidifierchamber housing 32.

FIG. 7 is a longitudinal cross-sectional view of the portable humidifier27 shown in FIG. 6. This further illustrates the fluid inlet port 30,which delivers fluid to the humidification chamber 35. Note the relativesmall size of the humidification chamber 35. This is a significantadvantage and greatly enhances the portability of the system. Also shownhere is the humidification element 33. In one embodiment, this elementis an ultrasonic element, such as a nebulizer, which vibrates to createthe humidity. Also pictured are several sealing elements 34.

FIG. 8 is a longitudinal cross-sectional view of yet another portablehumidifier 27. Here the fluid is introduced through the inlet port 30.It enters the integrated pump 50, which drives the fluid flow, pullingit from a fluid reservoir (not shown) and pushing into an optionalultraviolet (UV) sanitization chamber 60 where there is a UV lightsource 61 to kill microorganisms in the fluid as they pass through theUV treatment chamber 60. This UV light source 61 could be a UV LED. Fromthere, the fluid passes through a fluid channel 71, which takes thefluid along an optional heating element 70 which heats the fluid as itenters the humidification chamber 35. An optional fluid sensor 110 isshown monitoring the fluid level in the humidification chamber 35. Thisfluid sensor 110 senses the presence of fluid in the chamber, and canrelay these findings to regulate the control of the pump to maintain thedesired fluid level in the chamber. The resultant heated, sanitizedhumidification is shown here as 45.

FIG. 9 is a cross-sectional view of a fluid reservoir adaptor. Theadaptor 80 includes threads 84 allowing it to attach to standard waterbottles and other reservoirs. Incorporated in the adaptor is afiltration chamber 81, which houses filtration media 82. Filtrationmedia can filter the fluid for impurities. One embodiment has thefiltration media including demineralization media. This allows the userto utilize tap water in the system. The demineralization media removesany minerals in the tap water prior to aerosolization forhumidification. This provides significant safety and convenience for theuser.

FIG. 10 is a cross-sectional view of the fluid reservoir adaptor 80,showing an alternative outlet geometry for the fluid reservoir outlet83.

FIG. 11 is a cross-sectional view of a portable humidifier componentaccording to another embodiment of the invention. As in otherembodiments, the tubing integrated humidifier 27 connects to an airconduit (not shown) via inlet 25 and outlet 26. This design utilizes aheating element 91, which is housed in a base structure. Heat from theheating element 91 is transfer through a heat transfer material 92,which is integrated into a small fluid chamber 90. The level of fluid 93in chamber 90 is low, allowing for the heating element to only heat asmall amount of fluid at a time. This is more efficient and does notrequire the heating and maintaining the heat of a large reservoir offluid as most conventional humidifiers do. A fluid replenishment tube 94connected to the fluid reservoir (not shown) via fluid conduit 28 has anoutlet 95 which is a fixed distance from the bottom of chamber 90. Whenthe heated fluid evaporates into the airflow, the level of fluid 93 willdrop below the outlet 95 of the fluid replenishment tube 94. When thisoccurs, air is allowed to pass up the fluid replenishment tube to thelarge fluid reservoir (not shown), thereby allowing more fluid to enterthe chamber, up until the point where the outlet of the fluidreplenishment tube is again submerged. This effectively creates aself-regulating, self-replenishing system. The small amount of fluid tobe heated enables a much more efficient system.

FIG. 12 is a longitudinal cross-sectional view of a portable humidifieraccording to another embodiment of the invention. The fluid inlet port30 delivers fluid to the humidification chamber 35. Note the relativesmall size of the humidification chamber 35 with respect to the diameterof the air conduit formed in part by connectors 25 and 26. Thehumidification chamber 35 can hold a volume of about 0.1 cc to 5 cc ofwater. In one embodiment, the humidification chamber holds about 0.5 ccof fluid. This small size is a significant advantage as it greatlyenhances the portability of the system compared to conventional systemsfor humidification, which typically are sized to hold 350 cc to 500 cc.Also shown here is the humidification element 33. In one embodiment,this element is an ultrasonic element, such as a nebulizer, whichvibrates to create the humidity 45. Also pictured are several sealingelements 34. An absorbent element 100 is shown lining a portion of theinterior of the airflow lumen. The absorbent element 100 is comprised ofan absorbent material 101, such as hydrogels, fibers, cottons,synthetics, polymers, superabsorbent polymers, polyvinyl alcohols, andother materials known to be absorbent. This absorbent material 101 mayalso be wicking. This material removes excess moisture, especiallycondensate 102, from the airflow lumen. In one embodiment, the absorbentmaterial 101 absorbs excess moisture and then wicks it back to thehumidification element 33 to be aerosolized once again.

FIG. 13 is a longitudinal cross-sectional view of a portable humidifieraccording to another embodiment of the invention. The fluid inlet port30 delivers fluid to the humidification chamber 35. The humidificationelement 33 (such as, e.g., an ultrasonic nebulizer) transforms the fluidinto humidity 45. A condensate collection element 105 is shown lining aportion of the interior of the air flow lumen. This condensatecollection element 105 is designed to collect excess moisture in theform of condensate 102, and the concave condensation channel 106channels the condensate 102 back through the aperture for the return ofcondensate 107 to the humidification element 33 to be aerosolized onceagain. This allows excess moisture, especially condensate 102, to beremoved from the airflow lumen and aerosolized again. In this way, thesystems depicted in FIGS. 12 and 13 are self-regulating, allowing forthe optimum humidity to be maintained in the system. One embodiment ofthe system as depicted in FIG. 13 requires orientation relative togravity such that the fluid drains naturally via the concavecondensation channel 106 to return to the humidification element 33,when it is positioned on the bottom side of the tubing as shown in FIG.13.

FIGS. 14 a, b, and c are diagrammatic cross-sections showing variousembodiments allowing wicking and regulation of fluid flow from the fluidreservoir to the humidification element. FIG. 14a shows across-sectional side view of the tubing 28 connecting the fluidreservoir to the humidifier with a wicking material 120 in the lumen towick fluid from the reservoir to the humidification element. FIG. 14b isa diagrammatic cross-sectional side view of the tubing 28 connecting thefluid reservoir to the humidifier with a fluid valve 130, which could beone of many such valves, to aid in the transport of fluid from thereservoir to the humidifier. A combination of wicking material andvalves can provide for the transport of fluid. The one-way valves with alow cracking pressure allow for ease of forward flow while preventingback flow of fluid. FIG. 14c is a diagrammatic cross-sectional side viewof the tubing 28 connecting the fluid reservoir to the humidifier, witha self-regulating flow limiting structure included. The structureincludes a deflectable member 140, attached to rigid members 141. Thefluid flow channel 142 is sized to allow a flow rate up to the maximumdesired flow rate. When the pressure in the fluid tube 28 increases, thepressure deflects the deflectable member 140, further restricting thefluid flow channel 142, thereby keeping the flow rate within the desiredrange. When the pressure in the fluid tube 28 is reduced, thedeflectable member flexes back down, thereby increasing the lumen of thefluid channel 142, allowing greater flow. In this manner, the structureshown in FIG. 14c allows for the self-regulation of the flow rate fromthe reservoir to the humidifier. This embodiment can be particularlyuseful when the reservoir is placed higher than the humidifier andgravity provides the primary driving force for delivering fluid from thereservoir to the humidifier. This structure helps regulate fluid flowand prevent flow rates above a desired maximum flow rate.

FIG. 15 shows a cross-sectional side view of an alternative embodimentfor the humidifier. The humidification element 33 is mounted within afloating structure which has a portion of its structure above the fluidlevel 93, and a portion below. The humidification element 33 sits rightat the fluid level 93, such that it can access fluid from belowconsistently and create humidity 45 into the air above for transportwithin the air circuit. The humidifier inlet 25 and humidifier outlet 26communicate with the rest of the tubing to provide the humidifiedairflow to the user. An optional integrated heating element 70 is alsopictured, just below the humidification element. The heating element 70heats the fluid to the desired temperature prior to the humidificationprocess. This entire humidification structure sits within the fluidreservoir 21. As the fluid level 93 drops, the humidification structuredrops with it, remaining on the surface. This embodiment offers severaladvantages. There is no need to transport fluid from a reservoir to thehumidification element. There is no need to heat the entire fluidreservoir. The humidification element always has access to fluid forhumidification. This embodiment offers an alternative integratedhumidifier design.

A preferred embodiment of the system achieves humidification through theuse of an ultrasonic humidification element. This can entail apiezoelectric material that oscillates at ultrasonic frequencies tocreate tiny droplets of water, or mist. This approach offers severaladvantages. Ultrasonic elements can be made with a very small size,making them particularly well suited for portable applications.Additionally, they are relatively efficient in power use compared toother humidification technologies. Ultrasonic humidification can berealized in multiple ways. In one approach, the oscillating element isplaced beneath a small amount of water, and when it vibrates thedroplets are emitted from the surface of the water. In another form, thevibrating element has micro holes that allow for the passage of waterfrom a reservoir side to the opposite side where it is converted intodroplets of airborne water. Vibrating elements with holes can be moreefficient as they do not require the energy to pass through a mass ofwater to achieve the humidification. An additional advantage ofultrasonic humidification elements is their low cost.

An alternative embodiment utilizes a jet nebulizer to achieve humidityin the airflow. A compressed air source is used to force air throughwater at a high velocity, resulting in tiny droplets of water beingaerosolized. This system can use pressurized air selectively, timing itsrelease as needed to humidify the airstream.

An alternative embodiment utilizes a fluid introduction element withmicro perforations to introduce water to the airflow. By introducingtiny droplets of water in a multitude of locations, the passing airbecomes humidified.

An alternative embodiment utilizes a wicking element that humidifies theairflow through evaporation. Various materials can be used, from papers,to fibers, fabrics, ceramics and matrices of polymers can be used towick moisture from a source and into the air stream. By increasing theamount of surface area for evaporation, the amount of humidification canbe influenced. Wicking elements have an advantage of beingself-regulating. When the relative humidity is high, evaporation occursat a slower rate, thereby regulating the overall humidity to the user.

An alternative embodiment combines a weeping element with a porousdispersion material. The porous dispersion material is similar to asponge. The dispersion material is saturated with water, and includesgeometry to maximize its surface area and the creation of tiny dropletsof water. These droplets disperse into the airflow.

An alternative embodiment utilizes on demand heating for more efficientheated humidification. Prior art humidification systems utilize a hotplate heating element that heats up a large enough volume of water tolast through the night. This approach has several limitations. It takessome time for the heating element to bring the entire volume of water upto the desired temperature. It requires additional energy to keep theentire volume of water at temperature. These shortcomings can beovercome with on demand heating technology.

A small heating chamber is used to heat enough water to meet theevaporation and humidification demand of the system. This chamber iscontinually replenished from a larger reservoir of water. This largerreservoir does not need to be heated, saving energy. Only the relevantamount of water is heated, as it is needed. As the water in the smallheating chamber evaporates, it is replenished from the reservoir.Multiple replenishment mechanisms can be used. Gravity can be used toreplenish the heating chamber. This can be accomplished in aself-regulating way by having a refill tube enter the heating chambervertically from above, and stop short of contacting the base of thechamber interior. With the water reservoir sealed, the water will onlycome out of the refill tube when it can be replaced by air from theheating chamber.

This occurs once the water level in the heating chamber dips below thelevel of the tube opening. When the water level falls below the level ofthis opening, air will be allowed into the reservoir, and water willleave the reservoir until the tube opening is once again submerged inwater. This auto refill system ensures a steady, self-regulating amountof water in the heating chamber.

In another embodiment, the water level in the heating chamber isrefilled through the use of a pump 50. This approach can incorporate anoptional sensor system. A fluid sensor 110 placed at the desired levelin the heating chamber provides information on the fluid level, which isused to determine whether the chamber needs more water. A pump or valvesystem is then controlled to allow the desired amount of water to passfrom the reservoir to the heating chamber. A depiction of this isincluded in FIG. 8.

As described above, a way to transport water from the reservoir to theheating chamber is through the use of a wicking material. A wickingmaterial placed in the conduit between the reservoir and the heatingchamber transports water from the reservoir to the chamber. The wickingrate can be controlled by varying the wicking material, it's density,and the geometry of the conduit. Rate limiting valves can also beemployed to affect an upper limit on the rate of water transfer. Pumps,gravity, or pressurizing the reservoir can also be used in conjunctionwith wicking to achieve the desired fluid transfer rate.

Another embodiment of the invention utilizes a floating humidificationelement in the water reservoir. This eliminates the need to transportwater from the reservoir to the humidification element. It alsoeliminates the need to heat the entire reservoir of water. An elementwhich performs humidification and optionally also heating is placed in astructure which floats on the surface of the water. The floatationelement is designed such that a portion of the structure is kept abovethe water level, and another portion is below the water level. Water issourced by a pathway in the portion of the structure which is submerged.This allows the device to maintain the optimum desired level of water inthe humidification element. As the water reservoir empties throughoutuse, the floating structure simply lowers, staying on the surface of thewater. FIG. 15 is a depiction of this embodiment.

Any combination of the above described humidification elements ispossible, and in many cases will be most desirable. For example, anultrasonic element with a wicking material will distribute moistureevenly and consistently. Also, while the invention has been describedwith reference to PAP devices, the invention is also applicable to CPAP,XPAP, BiPAP, APAP and AutoPAP devices.

Although the description herein is focused on the application ofpositive airway pressure devices, especially for the treatment of sleepdisordered breathing, there are many other applications for thistechnology. Other applications where this technology is of clear useinclude ventilators, nebulizers, oxygen delivery systems, and otherrespiratory applications where humidification is advantageous.

Hose is a term common to the respiratory applications described herein,but it should be understood that other similar terms such as conduit,passageway, channel, tube and air path can also be used.

The terms water, fluid, and vapor are used herein, and it should beunderstood to include any fluid suitable for humidification inrespiratory applications, including fluids with added elements forcomfort or therapeutic purposes. Terms such as gas, gaseous, vapor,droplet, mist, aerosolized fluid are all meant to indicate fluidsconverted into an inhalable humidified form.

Variations and modifications of the devices and methods disclosed hereinwill be readily apparent to persons skilled in the art. As such, itshould be understood that the foregoing detailed description and theaccompanying illustrations, are made for purposes of clarity andunderstanding, and are not intended to limit the scope of the invention,which is defined by the claims appended hereto. Any feature described inany one embodiment described herein can be combined with any otherfeature of any of the other embodiment whether preferred or not.

It is understood that the examples and embodiments described herein arefor illustrative purposes only and that various modifications or changesin light thereof will be suggested to persons skilled in the art and areto be included within the spirit and purview of this application andscope of the appended claims. All publications, patents, and patentapplications cited herein are hereby incorporated by reference for allpurposes.

What is claimed is:
 1. A positive airway pressure system comprising: apatient interface; an air flow generator adapted to supply pressurizedair to the patient interface via a lumen of an air conduit; anultrasonic humidifier supported by the air conduit and in fluidcommunication with the air conduit lumen, the ultrasonic humidifiercomprising a humidification chamber and an ultrasound transducer adaptedto atomize water from the humidification chamber into the pressurizedair; and a water reservoir in fluid communication with thehumidification chamber of the ultrasonic humidifier, the water reservoirhaving a water storage capacity greater than a water storage capacity ofthe humidification chamber of the ultrasonic humidifier.
 2. The systemof claim 1 wherein the water reservoir is disposed above thehumidification chamber of the ultrasonic humidifier to deliver water bygravity from the water reservoir to the humidification chamber of theultrasonic humidifier.
 3. The system of claim 1 further comprising apump adapted to pump water from the water reservoir to thehumidification chamber of the ultrasonic humidifier.
 4. The system ofclaim 1 wherein the ultrasonic humidifier further comprises a powersource separate from a power source of the air flow generator.
 5. Thesystem of claim 1 further comprising a water conduit extending from thewater reservoir to the ultrasonic humidifier.
 6. The system of claim 5wherein the water conduit is integrated with the air conduit along atleast part of the length of the water conduit and at least part of thelength of the air conduit.
 7. The system of claim 1 wherein the systemfurther comprises a controller adapted to activate and de-activate theultrasound transducer.
 8. The system of claim 7 wherein the controlleris further adapted to activate and de-activate the ultrasound transducerin synchrony with inspiratory and expiratory phases of a user'sbreathing.
 9. The system of claim 1 further comprising a UV sanitizeradapted to provide UV radiation to water moving from the water reservoirto the humidification chamber.
 10. The system of claim 1 furthercomprising a heating element adapted to heat water in the humidificationreservoir.
 11. The system of claim 1 further comprising a water filterdisposed between the water reservoir and the humidification chamber. 12.The system of claim 1 wherein the air conduit comprises an absorbentelement adapted to remove excess moisture from the pressurized air. 13.The system of claim 12 wherein the absorbent material is further adaptedto wick moisture to the humidification chamber.
 14. The system of claim1 further comprising a condensate collection element in communicationwith the air conduit.
 15. The system of claim 14 wherein the condensatecollection element is in fluid communication with the humidificationchamber.
 16. The system of claim 14 wherein the condensate collectionelement is disposed below the air conduit to collect condensate bygravity.
 17. A positive airway pressure system comprising: a patientinterface; an air flow generator adapted to supply pressurized air tothe patient interface via a lumen of an air conduit; a water reservoir;and a humidifier comprising a humidification reservoir having a volumeless than the volume of the water reservoir and a heater adapted to heatwater in the humidification reservoir, the humidification reservoircommunicating with the air conduit lumen.
 18. The system of claim 17further comprising a water conduit extending from an outlet of the waterreservoir to the humidification reservoir, the water conduit having anoutlet disposed above a bottom surface of the humidification reservoirand below the outlet of the water reservoir so that water flows from thewater reservoir to the humidification reservoir when the water level inthe humidification reservoir drops below the outlet of the water conduitand water ceases flowing from the water reservoir to the humidificationreservoir when the water level in the humidification reservoir is abovethe outlet of the water conduit.
 19. The system of claim 17 furthercomprising a pump adapted to pump water from the water reservoir to thehumidification reservoir.
 20. The system of claim 19 further comprisinga water level sensor in the humidification reservoir operativelyconnected to the pump.
 21. The system of claim 17 further comprisingwicking material adapted to transport water from the water reservoir tothe humidification reservoir.